The processing of silver halide color photographic materials generally comprises a color-developing process and a desilvering process. The silver produced in the development is oxidized with a bleaching agent and then dissolved by the action of a fixing agent. As the bleaching agent, a ferric (III) ion complex salt (e.g., an aminopolycarboxylic acid/ferric (III) complex salt) is normally used, and as the fixing agent a thiosulfate is generally used.
On the other hand, the processing of black-and-white photographic materials comprises a developing process and a process for removing the unexposed silver halide, and it differs from the processing of color photographic materials in that the black-and-white photographic material is subjected to the fixing process without being subjected to a bleaching process after the development. Also in this case, as the fixing agent, generally a thiosulfate is used.
In recent years, reduction of the replenisher volume of photographic processing solutions has been vigorously studied. This is also true for the bath having fixing capacity. As low-replenishing-rate processing proceeds, the amount of silver ions and halide ions (e.g., iodide ions, bromide ions, and chloride ions) that accumulate in the running exhausted solution increase, resulting in slowing of fixing, which is a serious problem, and therefore a solution composition is desired with which, even when low-replenishing-rate processing is effected, the fixing is not delayed.
Further, the stability of solutions becomes a problem because of the elongation of retention time at the low-replenishment-rate processing. In particular, thiosulfates that are used widely as fixing agents have a problem of sulfur-deposit. An improvement of this problem is highly desired.
To improve the above-described problem, conventionally thiocyanate ions (e.g., ammonium thiocyanate and sodium thiocyanate) are added into a fixing solution, but the delay in the fixing is not satisfactorily improved and there is concern about the influence of thiocyanate ions on the environment, and therefore more effective materials are desired.